sbin/fsck_msdosfs/boot.c

45 	u_char block[DOSBOOTBLOCKSIZE];
51 	if (read(dosfs, block, sizeof block) != sizeof block) {
52 		perror("could not read boot block");
56 	if (block[510] != 0x55 || block[511] != 0xaa) {
57 		pfatal("Invalid signature in boot block: %02x%02x",
58 		    block[511], block[510]);
65 	/* decode bios parameter block */
66 	boot->bpbBytesPerSec = block[11] + (block[12] << 8);
67 	boot->bpbSecPerClust = block[13];
68 	boot->bpbResSectors = block[14] + (block[15] << 8);
69 	boot->bpbFATs = block[16];
70 	boot->bpbRootDirEnts = block[17] + (block[18] << 8);
71 	boot->bpbSectors = block[19] + (block[20] << 8);
72 	boot->bpbMedia = block[21];
73 	boot->bpbFATsmall = block[22] + (block[23] << 8);
74 	boot->SecPerTrack = block[24] + (block[25] << 8);
75 	boot->bpbHeads = block[26] + (block[27] << 8);
76 	boot->bpbHiddenSecs = block[28] + (block[29] << 8) +
77 	    (block[30] << 16) + (block[31] << 24);
78 	boot->bpbHugeSectors = block[32] + (block[33] << 8) +
79 	    (block[34] << 16) + (block[35] << 24);
86 		boot->FATsecs = block[36] + (block[37] << 8)
87 				+ (block[38] << 16) + (block[39] << 24);
88 		if (block[40] & 0x80)
89 			boot->ValidFat = block[40] & 0x0f;
92 		if (block[42] || block[43]) {
95 			       block[43], block[42]);
98 		boot->bpbRootClust = block[44] + (block[45] << 8)
99 			       + (block[46] << 16) + (block[47] << 24);
100 		boot->bpbFSInfo = block[48] + (block[49] << 8);
101 		boot->bpbBackup = block[50] + (block[51] << 8);
106 			perror("could not read fsinfo block");
119 			pwarn("Invalid signature in fsinfo block\n");
157 		backup[65] = block[65];				/* XXX */
158 		if (memcmp(block + 11, backup + 11, 79)) {
168 			pfatal("backup (block %d) mismatch with primary bootblock:\n",
171 				if (block[i] != backup[i])
173 					       i, block[i], backup[i]);
245 		perror("could not read fsinfo block");
267 	 * support for FAT32) doesn't maintain the FSINFO block
270 	 * Therefor, we handle the FSINFO block only informally,